A nuclear family consists of

A substance that is made up of a single kinf of atom is called

Kitty [74]

A chemical element is a substance that is made up of only one kind atom.

7 0

3 years ago

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Which of the following sign does not indicate that a chemical change has happened .

Sever21 [200]

Answer:

A.)

Explanation:

A change in state may seem like a chemical reaction, but it is actually a physical change. "A change in state" is basically saying that the appearance of whatever the item is, is taking a change physically. Whether this item was going through some examples of a physical change, which would be:

melting (solid to liquid), evaporation (liquid to gas), condensation (gas to liquid), freezing (liquid to solid), deposition (gas to solid), and sublimation (solid to gas).

A change in color, odor, taste, chemical compound, and temperature all represent a chemical reaction, because these are all things that are happening within the the item that is being given the product of a chemical change.

Think of it this way: internal changes within the product: chemical. External changes within the product: physical.

I hope this helps.

4 0

2 years ago

Neutral atoms of all the isotopes of the same element have

Viktor [21]

Answer:

electron = proton

Explanation:

6 0

2 years ago

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We make a basic solution by mixing 50. mL of 0.10 M NaOH and 50. mL of 0.10 M Ca(OH)2. It requires 250 mL of an HCl solution to

andreyandreev [35.5K]

Answer: The correct answer is Option 5.

Explanation:

To calculate the molarity of the solution after mixing 2 solutions, we use the equation:

$M=\frac{n_1M_1V_1+n_2M_2V_2}{V_1+V_2}$

where,

$n_1,M_1\text{ and }V_1$ are the n-factor, molarity and volume of the NaOH.

$n_2,M_2\text{ and }V_2$ are the n-factor, molarity and volume of the $Ca(OH)_2$

We are given:

$n_1=1\\M_1=0.10M\\V_1=50mL\\n_2=2\\M_2=0.1\\V_2=50mL$

Putting all the values in above equation, we get:

$M=\frac{(1\times 0.1\times 50)+(2\times 0.1\times 50)}{50+50}\\\\M=0.15M$

To calculate the molarity of acid, we use the equation given by neutralization reaction:

$n_1M_1V_1=n_2M_2V_2$

where,

$n_1,M_1\text{ and }V_1$ are the n-factor, molarity and volume of acid which is $HCl$

$n_2,M_2\text{ and }V_2$ are the n-factor, molarity and volume of base.

We are given:

$n_1=1\\M_1=?M\\V_1=250mL\\n_2=1\\M_2=0.15M\\V_2=100mL$

Putting values in above equation, we get:

$1\times M_1\times 250=1\times 0.15\times 100\\\\M_1=0.06M$

Hence, the correct answer is Option 5.

7 0

3 years ago

You are asked to go into the lab and prepare an acetic acid - sodium acetate buffer solution with a ph of 4.00  0.02. what mola

Oxana [17]

Hello!

To solve this problem we are going to use the Henderson-Hasselbach equation and clear for the molar ratio. Keep in mind that we need the value for Acetic Acid's pKa, which can be found in tables and is 4,76:

$pH=pKa + log ( \frac{[CH_3COONa]}{[CH_3COOH]} )$

$\frac{[CH_3COOH]}{[CH_3COONa}= 10^{(pH-pKa)^{-1}}=10^{(4-4,76)^{-1}}=5,75$

So, the mole ratio of CH₃COOH to CH₃COONa is 5,75

Have a nice day!

5 0

3 years ago